The most common way to form a superlative (best, worst, fattest, most complex, etc.) in Chinese is to use 最 (zuì) before an adjective.
Basic Structure:
最+Adjective
And now you have the superlative form of the adjective. Unlike in English, this structure is consistent for all adjectives in Chinese.
Examples:
Tā zuì bèn.
他 最 笨。
他 最 笨。
He is the dumbest.
Optional 不过了(búɡuòle):
Occasionally you'll also see a "不过了" or just a "了" added after the adjective. This adds emphasis to the "-est."
最+Adjective+（不过了）
Examples:
Tā zuì cōnɡmínɡ búɡuòle.
他 最 聪明 不过了。
他 最 聪明 不过了。
He is the smartest.
Wǒ zuì ɡāo le.
我 最 高 了。
我 最 高 了。
I am the tallest.
